Bare Feats:

If these four tests are indicative, Lightroom is faster to process adjustments while Aperture is faster to process exports.

This explains why I think Lightroom is faster, exporting is only a small part of what I do with images, and I rarely do it in large batches. Export tests are dumb in my opinion because it is going to take time no matter what, I want my workflow while I am at the machine to be fast. I can drink some scotch while stuff exports.